The direct ortho‐alkynylation of substituted phenylalanine has been successfully achieved through methoxyiminoacyl (MIA)‐mediated Pd‐catalyzed C‐H functionalization. This innovative protocol showcases the ability to apply a diverse range of phenylalanine substrates, resulting in the efficient synthesis of alkynylation benzylamine derivatives with notable effectiveness. Computational investigations further revealed that the fluoride ion enhances the electropositivity of Pd(IV) and the interaction between C1 and C2 within the transition state of the reductive elimination, which significantly expedites the reductive elimination step in the alkynylation process.